gpio-logicvc.c

  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Copyright (C) 2019 Bootlin
  4 * Author: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
  5 */
  6
  7#include <linux/err.h>
  8#include <linux/gpio/driver.h>
  9#include <linux/module.h>
 10#include <linux/of.h>
 11#include <linux/of_address.h>
 12#include <linux/platform_device.h>
 13#include <linux/regmap.h>
 14#include <linux/mfd/syscon.h>
 15
 16#define LOGICVC_CTRL_REG		0x40
 17#define LOGICVC_CTRL_GPIO_SHIFT		11
 18#define LOGICVC_CTRL_GPIO_BITS		5
 19
 20#define LOGICVC_POWER_CTRL_REG		0x78
 21#define LOGICVC_POWER_CTRL_GPIO_SHIFT	0
 22#define LOGICVC_POWER_CTRL_GPIO_BITS	4
 23
 24struct logicvc_gpio {
 25	struct gpio_chip chip;
 26	struct regmap *regmap;
 27};
 28
 29static void logicvc_gpio_offset(struct logicvc_gpio *logicvc, unsigned offset,
 30				unsigned int *reg, unsigned int *bit)
 31{
 32	if (offset >= LOGICVC_CTRL_GPIO_BITS) {
 33		*reg = LOGICVC_POWER_CTRL_REG;
 34
 35		/* To the (virtual) power ctrl offset. */
 36		offset -= LOGICVC_CTRL_GPIO_BITS;
 37		/* To the actual bit offset in reg. */
 38		offset += LOGICVC_POWER_CTRL_GPIO_SHIFT;
 39	} else {
 40		*reg = LOGICVC_CTRL_REG;
 41
 42		/* To the actual bit offset in reg. */
 43		offset += LOGICVC_CTRL_GPIO_SHIFT;
 44	}
 45
 46	*bit = BIT(offset);
 47}
 48
 49static int logicvc_gpio_get(struct gpio_chip *chip, unsigned offset)
 50{
 51	struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
 52	unsigned int reg, bit, value;
 53	int ret;
 54
 55	logicvc_gpio_offset(logicvc, offset, &reg, &bit);
 56
 57	ret = regmap_read(logicvc->regmap, reg, &value);
 58	if (ret)
 59		return ret;
 60
 61	return !!(value & bit);
 62}
 63
 64static int logicvc_gpio_set(struct gpio_chip *chip, unsigned int offset,
 65			    int value)
 66{
 67	struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
 68	unsigned int reg, bit;
 69
 70	logicvc_gpio_offset(logicvc, offset, &reg, &bit);
 71
 72	return regmap_update_bits(logicvc->regmap, reg, bit, value ? bit : 0);
 73}
 74
 75static int logicvc_gpio_direction_output(struct gpio_chip *chip,
 76					 unsigned offset, int value)
 77{
 78	/* Pins are always configured as output, so just set the value. */
 79	return logicvc_gpio_set(chip, offset, value);
 80}
 81
 82static struct regmap_config logicvc_gpio_regmap_config = {
 83	.reg_bits	= 32,
 84	.val_bits	= 32,
 85	.reg_stride	= 4,
 86	.name		= "logicvc-gpio",
 87};
 88
 89static int logicvc_gpio_probe(struct platform_device *pdev)
 90{
 91	struct device *dev = &pdev->dev;
 92	struct device_node *of_node = dev->of_node;
 93	struct logicvc_gpio *logicvc;
 94	int ret;
 95
 96	logicvc = devm_kzalloc(dev, sizeof(*logicvc), GFP_KERNEL);
 97	if (!logicvc)
 98		return -ENOMEM;
 99
100	/* Try to get regmap from parent first. */
101	logicvc->regmap = syscon_node_to_regmap(of_node->parent);
102
103	/* Grab our own regmap if that fails. */
104	if (IS_ERR(logicvc->regmap)) {
105		struct resource res;
106		void __iomem *base;
107
108		ret = of_address_to_resource(of_node, 0, &res);
109		if (ret) {
110			dev_err(dev, "Failed to get resource from address\n");
111			return ret;
112		}
113
114		base = devm_ioremap_resource(dev, &res);
115		if (IS_ERR(base))
116			return PTR_ERR(base);
117
118		logicvc_gpio_regmap_config.max_register = resource_size(&res) -
119			logicvc_gpio_regmap_config.reg_stride;
120
121		logicvc->regmap =
122			devm_regmap_init_mmio(dev, base,
123					      &logicvc_gpio_regmap_config);
124		if (IS_ERR(logicvc->regmap)) {
125			dev_err(dev, "Failed to create regmap for I/O\n");
126			return PTR_ERR(logicvc->regmap);
127		}
128	}
129
130	logicvc->chip.parent = dev;
131	logicvc->chip.owner = THIS_MODULE;
132	logicvc->chip.label = dev_name(dev);
133	logicvc->chip.base = -1;
134	logicvc->chip.ngpio = LOGICVC_CTRL_GPIO_BITS +
135			      LOGICVC_POWER_CTRL_GPIO_BITS;
136	logicvc->chip.get = logicvc_gpio_get;
137	logicvc->chip.set = logicvc_gpio_set;
138	logicvc->chip.direction_output = logicvc_gpio_direction_output;
139
140	return devm_gpiochip_add_data(dev, &logicvc->chip, logicvc);
141}
142
143static const struct of_device_id logicivc_gpio_of_table[] = {
144	{
145		.compatible	= "xylon,logicvc-3.02.a-gpio",
146	},
147	{ }
148};
149
150MODULE_DEVICE_TABLE(of, logicivc_gpio_of_table);
151
152static struct platform_driver logicvc_gpio_driver = {
153	.driver	= {
154		.name		= "gpio-logicvc",
155		.of_match_table	= logicivc_gpio_of_table,
156	},
157	.probe	= logicvc_gpio_probe,
158};
159
160module_platform_driver(logicvc_gpio_driver);
161
162MODULE_AUTHOR("Paul Kocialkowski <paul.kocialkowski@bootlin.com>");
163MODULE_DESCRIPTION("Xylon LogiCVC GPIO driver");
164MODULE_LICENSE("GPL");